<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        p,
        div {
            width: 100px;
        }
    </style>
</head>

<body>
    <!-- 块元素 自带外边距 -->
    <p>段落</p>
    <div>盒子</div>
    <!-- h1-h6块元素自带外边距 -->
    <h1>标题标签</h1>
</body>

</html>